Hun Sen spoke in response to last week's ruling by the tribunal allowing prosecutors to pursue further arrests. The matter had been in contention because the Cambodian co-prosecutor opposed the idea, while his international counterpart supported it.

The tribunal is seeking justice for the estimated 1.7 million people who died in Cambodia from execution, overwork, disease and malnutrition as a result of the communist regime's radical policies while in power between 1975-79.

Critics allege that Hun Sen has sought to limit the tribunal's scope because other potential defendants are now his political allies. Hun Sen served as a Khmer Rouge officer, before changing sides, and many of his major political allies are also former members of the group.

Brad Adams, Asia director at New York-based Human Rights Watch, said he believed Hun Sen was seeking to protect members of his own Cambodian People's Party, who could be targets for prosecution. But he said it was unlikely more arrests would be made.

"(Hun Sen) has been saying the same thing for 10 years, since before the court was set up," Adams said. "It's never happened, and it's not going to happen."

He pointed out that the Khmer Rouge have been defunct for a decade, and that its former leaders are more interested in business than war, and even if they sought to fight, they would be unable to recruit anyone to their side.

The tribunal's long-awaited first trial — of the Khmer Rouge's chief jailer, for war crimes and crimes against humanity — opened in March. A joint trial with four other senior officials — the only others currently in detention — is expected in the next year or two.

Hun Sen said that if foreign aid donors stopped funding the tribunal, Cambodia would carry on the proceedings on its own, without the international participation it now has. The tribunal employs joint teams of Cambodian and international court personnel.

"I would like to tell you that if you prosecute (more leaders) without thinking beforehand about national reconciliation and peace, and if war breaks out again and kills 20,000 or 30,000 people, who will responsible?" Hun Sen said. He said he was not trying to use his influence against the court, but only stating the situation.

There was no immediate reaction to Hun Sen's comment by representatives of the tribunal.

The Khmer Rouge came to power after a bitter 1970-75 civil war, and after being ousted from power in 1979, carried out an insurgency from the jungle until 1999.

Hun Sen said that he had devoted several years of his life to persuading Khmer Rouge leaders and their soldiers to end their fighting, so he could not allow anyone to drag the country back into a new civil war.

"I will not allow anyone to destroy what I have achieved,' Hun Sen said. "The value of peace here is huge."

Hun Sen has dominated Cambodian politics for more than two decades. He ousted his former co-prime minister in a 1997 coup and has since ruled virtually unchallenged.